<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script type="text/javascript">
    //基本数据类型
    //string
    //number
    //boolean
    //undefined
    // Null类 null
    //object 对象类型

    //弱类型
    var a = 2+"5";
    console.log(a, typeof(a));

    //无整型和浮点型之分
    var b = 10, c = 1.5;
    console.log(b, typeof(b), c, typeof(c));

    //布尔类型
    var e = true, f = false;
    console.log(e, typeof(e), f, typeof(f))

    //空值类型
    var g = null ; //None python
    console.log(g, typeof(g));

    //对象和数组
    var  lst = ["a","b","cefg",'edg']; //arrry
    var  dict = {firstname:"wen",lastname:"yao"}; //
    console.log(lst, typeof(lst), dict, typeof(dict))

    console.log(h, typeof(h));
    var h ="test";

    var x = "x";
    console.log(x, typeof(x))

    //压缩  最好行末加分号
    //通俗来讲，如果一条语句以 "(" ,"[" , "/" , "+" , "-" 开始，它们极有可能和前面一条语句一起解析。
    var $b = "1";
    var $a = "2";
    y = "1"
    console.log(y)

</script>

</body>
</html>